ShKo Bungalow at Karjat

The design for the ShKo bungalow at Karjat has finally been completed. It’s taken a lot longer than most because, apart from the complex slope, there was a severe constraint of building within a small portion of the entire one acre plot — the rest is prone to occasional flooding from the adjoining river.

Like other architectural designs, this too makes maximum use of local materials and of passive cooling.  External stone walls are at least 24″ (60cm) thick and provide a formidable barrier to heat-gain even in a place like Karjat.  Deep verandahs on the South and West don’t allow direct egress of strong sunlight from mid-mornings till evening. And high roofs with openings at upper levels allow constant ventilation to take place.

Rainwater harvested from the roof will be collected in the basement that is automatically formed by the sloping land. It will also be used to flood the pool which will not, hopefully, have any chemicals used to disinfect it. The current plan is to do natural filtration but the eventual system will depend on getting a reliable and qualified consultant to carry this out.

View from the gate

Picture 1 of 5

The entrance is set within a recess adjoining the car-port. Deep roof overhangs protect most walls from direct heat-gain. All external walls are at least 24" (60cm) thick and made of local stone to keep the interiors cool even in summer.

Glass Curtain Walls

Glass_Façade

Glass curtain walls and façades, seen as signs of modernity & progress, are inappropriate for our tropical climate.

Unfortunately, there is a strong trend in India these days towards designing building with glass curtain walls. These are seen as making a break from the bad old days when we were perennially short of power and couldn’t afford to run air-conditioning to keep ourselves cool. Well, I have some news for people with this view — we’re still perennially short of power and cannot afford to run so much air-conditioning.

Our country has a huge shortfall of electric power and that’s not going to change any time soon — at least not unless we suddenly manage to generate power from cold-fusion. In the meanwhile, huge quantities of fossil fuel will continue to be burned thereby exacerbating climate change and making things even worse for everybody and their pet dog.

Glass curtain-wall buildings are inappropriate for our climate for two reasons:

  1. Having a glass skin means that the inside is subjected to an enhanced greenhouse effect. Glass easily allows short wavelength light to pass through. Once this light has reflected off objects in the room, is of a longer wavelength which glass blocks. As a result, the internal temperature of the building builds up because the heat has now been trapped.
  2. This trapped heat has, somehow, to be expelled and – since there is never any significant natural ventilation in a glass building – this calls for massive (and environmentally expensive) air-conditioning. Let us not also forget that living and working in permanently enclosed spaces leads what is known as “sick building syndrome”.

Heat-reducing glass is like a pick-pocket returning your empty wallet.

Glass manufacturers will claim that their specialised products reduce heat build-up by 30%-40%. What they don’t tell you that not having a glass wall in the first place will reduce your heat-gain by twice that amount!

Another specious argument put forth is that using glass walls reduces the usage of electricity for lighting. Again, this is half-truth. Let us, for a moment, leave aside the amount of glare that people working inside such buildings have to put up with.

Consider a 10m² space.  Under normal circumstances, the air-conditioning load would be about 3,500W (or 2,500kW if you’re using a highly efficient HVAC system).  Lighting the space needs less than 100W if you’re using fluorescent lights and even less if you’re using LED fittings.

Now, the maximum saving you can achieve in lighting is 100W. On the other hand, your HVAC energy requirements will increase exponentially.  Even if expensive special glass is used, I’m afraid no amount of mathematical spin can bury this simple fact.

There are other aspects too, although unrelated to energy consumption. Migratory birds get confused by the glass and often die or sustain critical injuries when they slam against the huge transparent panes.

Further, if you happen to be in a glass building during a fire, there is no scope for ventilation so you asphyxiate–unless the glass curtain wall shatters, thereby endangering both, you and your rescuers from the fire department.

Passive Cooling in Tropical Climates

Passive cooling In tropical climates can be achieved by intelligent architectural design.In tropical climates, it’s important to keep the interior of a building cool and it is known as “passive cooling” because the reliance on “active” or mechanical means (air-conditioning) is kept to a minimum. In most parts of India, it is wise to keep direct sun away from the interiors of the building especially during the hot months. Allowing direct egress and glare leads to a build-up of heat and discomfort. This can be avoided by having deep roof overhangs and chajjas. Other methods of passive cooling depend on the local climatic factors.

Thermal Mass

In extreme climates which are usually also dry, you want to insulate yourself from the elements. For example in parts of Madhya Pradesh and Rajasthan, a hot and sand-laden wind (known as loo) is common in May. Under such circumstances, cross ventilation is something that you desperately want to avoid. In places like this, the openings are kept small and the walls are made so thick that by the time the heat manages to penetrate, the day is more or less over. Also, if you look at the local architecture, you will notice that all the structures are huddled together as if protecting each other from their harsh surroundings; which is, in fact, exactly what they’re doing.

Sun Studies

Sun Study

With the advent of computers and advanced software, what was once a tedious and error-prone manual procedure can now be completed by pressing a button. Sun studies help immensely in determining where and when sunlight enters a building, allowing the architect to accurately design awnings, verandahs and roof overhangs and even help in the placement of large trees which can provide shade.

The animation above was created using ArchiCAD – a parametric architectural package which is excellent, not only because one can design directly in 3D but, also, because it automatically calculates shadows for a given structure at any chosen date and time.

Cross Ventilation

In humid places like the coastal areas of our country, comfort is achieved by having air flowing over your skin; evaporating the sweat and cooling your body. For this, it is advisable to have large openings in the building’s envelope. However, deep overhangs need to be used to minimise direct entry of sunlight (read: heat) otherwise you’ll have hot air blowing over you, which pretty much defeats the purpose of the exercise, doesn’t it?

Clerestory windows help hot air escape

High-level clerestory windows help hot air escape

In addition, openings can be strategically placed to allow the heat to escape. In a single-storey house, high-level or clerestory windows allow hot air to escape and thus generate circulation even when there is very little natural breeze.

Another way to set up a stack effect is to install a wind-driven roof vent. They need no electricity to run and spin based on the difference between outside and inside temperature – the hotter it is outside, the faster they go. They can be purchased from:

Wind Vent :: Tamil Nadu
FlexiTuff Industries :: Maharashtra


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Energy

We can easily save energy and reduce our energy consumption by taking a few simple steps. Most are not too expensive and they pay back fairly quickly.

Solar Hot Water

It’s one of the cheapest and simplest ways to save a huge amount of energy and the payback period is pretty short. The panels to be installed are basic and require very little maintenance. Essentially, the technology consists of nothing but copper pipes which zigzag behind a glass pane and heat the water that runs through them. This water is stored in an insulated tank so that if you wake up at the crack of dawn and try to have a bath, there’ll probably be some warm water for you to use. That’s if you didn’t use it up the previous night.
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Passive Cooling in Tropical Climates

For centuries, until the invention of electricity, architects simply had to take into account the ways of the weather so that the interior of a home or workplace was comfortable for its tenants. In India, it led to the development of the Vastu Shastras – an ancient science that has now been obfuscated into a first class superstition… But that’s another story.
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Energy-Efficient Lighting

The incandescent bulb is the most common – and one of the most wasteful – ways of lighting a space. Today we have numerous fluorescent type fittings; both, the old tubelight as well as modern compacts which retro-fit into incandescent holders. Light Emitting Diodes – LEDs are rapidly getting cheaper and have now reached a level of affordability.
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Star Rated Equipment

India’s Bureau of Energy Efficiency (BEE) has created a system of energy rating for a large range of appliances, equipment and light fixtures. Air-conditioners are, of course, the biggest guzzlers here and, while the initial expense is high if you choose, say, an inverter type, consistent use over time will more than offset the cost. BEE has created an interactive Energy Calculator to tell you how much you would save for different ratings of air conditioners.

Glass Façades in Tropical Climates

In our country today, glass-walled buildings are looked upon as indicative of progress and modernity and an international aesthetic. But the fallout of using such climatically inappropriate designs, is soaring energy consumption and sick-building syndrome.
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